arXiv:physics/0612143 · Physical Review A

Dynamical interferences to probe short-pulse photoassociation of Rb atoms and stabilization of Rb2 dimers

Jordi Mur-Petit, Eliane Luc-Koenig, Françoise Masnou-Seeuws

Published Jun 21, 2007• 17 citations

Abstract

We analyze the formation of ${\mathrm{Rb}}_{2}$ molecules with short photoassociation pulses applied to a cold $^{85}\mathrm{Rb}$ sample. A pump laser pulse couples a continuum level of the ground electronic state $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$ with bound levels in the ${0}_{u}^{+}(5S+5{P}_{1∕2})$ and ${0}_{u}^{+}(5S+5{P}_{3∕2})$ vibrational series. The nonadiabatic coupling between the two excited channels induces time-dependent beatings in the populations. We propose to take advantage of these oscillations to design further laser pulses that probe the photoassociation process via photoionization or that optimize the stabilization in deep levels of the ground state.

DOI: 10.1103/physreva.75.061404

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Dynamical interferences as a probe of short-pulse-photoassociated rubidium dimer

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Short-pulse photoassociation in rubidium below the D1 line

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Pump-probe study of the formation of rubidium molecules by ultrafast photoassociation of ultracold atoms

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Formation of cold molecules by shaping with light the short-range interaction between cold atoms: photoassociation with strong laser pulses

Mihaela Vatasescu

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Cold molecules formation by shaping with light the short-range interaction between cold atoms: photoassociation with strong laser pulses

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arXiv:0906.1918Jun 10, 20090 citations

arXiv:physics/0612143 · Physical Review A

Dynamical interferences to probe short-pulse photoassociation of Rb atoms and stabilization of Rb2 dimers

Jordi Mur-Petit, Eliane Luc-Koenig, Françoise Masnou-Seeuws

Published Jun 21, 2007• 17 citations

arXiv HTML PDF

Abstract

We analyze the formation of

{\mathrm{Rb}}_{2}

molecules with short photoassociation pulses applied to a cold

^{85}\mathrm{Rb}

sample. A pump laser pulse couples a continuum level of the ground electronic state

X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}

with bound levels in the

{0}_{u}^{+}(5S+5{P}_{1∕2})

and

{0}_{u}^{+}(5S+5{P}_{3∕2})

vibrational series. The nonadiabatic coupling between the two excited channels induces time-dependent beatings in the populations. We propose to take advantage of these oscillations to design further laser pulses that probe the photoassociation process via photoionization or that optimize the stabilization in deep levels of the ground state.

DOI: 10.1103/physreva.75.061404

Related papers

Dynamical interferences as a probe of short-pulse-photoassociated rubidium dimer

Jordi Mur-Petit, Eliane Luc-Koenig, Françoise Masnou-Seeuws

We analyze the formation of Rb_2 molecules with short photoassociation pulses applied to a cold Rb-85 sample. The laser field couples a continuum level of the ground electronic state X ^1 Sigma_g^+ with bound levels in the 0_u^+(5S+5P_{1/2}) and 0_u^+(5S+5P_{3/2}) vibrational series. The non-adiabatic coupling between the two excited channels induces time-dependent beatings in the populations. We propose to take advantage of these oscillations either to probe the photoassociation process via a photoionization pulse, or to optimize the stabilization step into deep levels of the ground state.We analyze the formation of Rb_2 molecules with short photoassociation pulses applied to a cold Rb-85 sample. The laser field couples a continuum level of the ground electronic state X ^1 Sigma_g^+ with bound levels in the 0_u^+(5S+5P_{1/2}) and 0_u^+(5S+5P_{3/2}) vibrational series. The non-adiabatic coupling between the two excited channels induces time-dependent beatings in the populations. We propose to take advantage of these oscillations either to probe the photoassociation process via a photoionization pulse, or to optimize the stabilization step into deep levels of the ground state.

Dec 14, 20060 citations

Short-pulse photoassociation in rubidium below the D1 line

Christiane P. Koch, Ronnie Kosloff, Françoise Masnou-Seeuws

Photoassociation of two ultracold rubidium atoms and the subsequent formation of stable molecules in the singlet ground and lowest triplet states is investigated theoretically. The method employs laser pulses inducing transitions via excited states correlated to the $5S+5{P}_{1∕2}$ asymptote. Weakly bound molecules in the singlet ground or lowest triplet state can be created by a single pulse while the formation of more deeply bound molecules requires a two-color pump-dump scenario. More deeply bound molecules in the singlet ground or lowest triplet state can be produced only if efficient mechanisms for both pump and dump steps exist. While long-range $1∕{R}^{3}$ potentials allow for efficient photoassociation, stabilization is facilitated by the resonant spin-orbit coupling of the ${0}_{u}^{+}$ states. Molecules in the singlet ground state bound by a few wave numbers can thus be formed. This provides a promising first step toward ground-state molecules which are ultracold in both translational and vibrational degrees of freedom.Photoassociation of two ultracold rubidium atoms and the subsequent formation of stable molecules in the singlet ground and lowest triplet states is investigated theoretically. The method employs laser pulses inducing transitions via excited states correlated to the $5S+5{P}_{1∕2}$ asymptote. Weakly bound molecules in the singlet ground or lowest triplet state can be created by a single pulse while the formation of more deeply bound molecules requires a two-color pump-dump scenario. More deeply bound molecules in the singlet ground or lowest triplet state can be produced only if efficient mechanisms for both pump and dump steps exist. While long-range $1∕{R}^{3}$ potentials allow for efficient photoassociation, stabilization is facilitated by the resonant spin-orbit coupling of the ${0}_{u}^{+}$ states. Molecules in the singlet ground state bound by a few wave numbers can thus be formed. This provides a promising first step toward ground-state molecules which are ultracold in both translational and vibrational degrees of freedom.

arXiv:physics/0511235Physical Review AApr 13, 200673 citations

Pump-probe study of the formation of rubidium molecules by ultrafast photoassociation of ultracold atoms

David J. McCabe, Duncan G. England, Hugo E. L. Martay +5 more

An experimental pump-probe study of the photoassociative creation of translationally ultracold rubidium molecules is presented together with numerical simulations of the process. The formation of loosely bound excited-state dimers is observed as a first step toward a fully coherent pump-dump approach to the stabilization of ${\text{Rb}}_{2}$ into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of preassociated molecules.An experimental pump-probe study of the photoassociative creation of translationally ultracold rubidium molecules is presented together with numerical simulations of the process. The formation of loosely bound excited-state dimers is observed as a first step toward a fully coherent pump-dump approach to the stabilization of ${\text{Rb}}_{2}$ into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of preassociated molecules.

arXiv:0904.0244Physical Review ASep 3, 200926 citations

The formation of ultracold rubidium molecules using ultrafast photoassociation

David J. McCabe, David J. McCabe

The establishment of robust laser-cooling techniques for the formation of ultracold atoms has provided a test-bed for low-temperature science, with scattering events changing character from incoherent thermal interactions to coherent quantum mechanical events. A natural extension is the pursuit of ultracold molecules in prescribed low-energy internal states. Atomic cooling techniques, however, do not generalize to the molecular regime due to the complex energy-level structure afforded by its extra degrees of motion. An indirect approach to ultracold molecule formation - photoassociation using ultrafast laser pulses - is the focus of this thesis. A broadband field associates atom pairs into a localized molecular wavepacket that evolves within the attractive excited-state potential. A suitably timed dump pulse may thus be applied to stabilize population into deeply bound ground vibrational states. This strategy may be generalized to any species whose spectroscopy matches the pulse spectrum, and offers a coherent population transfer scheme that does not require precise knowledge of the system. This thesis presents experiments using high-energy photoassociation pulses applied to ultracold rubidium atoms. The pulses quench the background ground-state molecular population but form bound dimers within the excited state. A pump-probe experiment was designed to chart the excited-state dynamics; however, the oscillations predicted by theoretical calculations were not evident in the molecular signal. The nature of the dynamics is expected to be strongly dependent on the initial state of the atom pairs addressed by the ultrafast pulse: a bound molecular population provides an additional candidate to free atoms. A spectroscopic measurement characterizes these bound molecules and identifies their formation mechanism. A subsequent experiment provides evidence that the predominant contributor to the pump-probe signal is the unbound initial population. The consequences with regard to both the observation of excited-state dynamics and the subsequent application of a dump pulse are discussed.The establishment of robust laser-cooling techniques for the formation of ultracold atoms has provided a test-bed for low-temperature science, with scattering events changing character from incoherent thermal interactions to coherent quantum mechanical events. A natural extension is the pursuit of ultracold molecules in prescribed low-energy internal states. Atomic cooling techniques, however, do not generalize to the molecular regime due to the complex energy-level structure afforded by its extra degrees of motion. An indirect approach to ultracold molecule formation - photoassociation using ultrafast laser pulses - is the focus of this thesis. A broadband field associates atom pairs into a localized molecular wavepacket that evolves within the attractive excited-state potential. A suitably timed dump pulse may thus be applied to stabilize population into deeply bound ground vibrational states. This strategy may be generalized to any species whose spectroscopy matches the pulse spectrum, and offers a coherent population transfer scheme that does not require precise knowledge of the system. This thesis presents experiments using high-energy photoassociation pulses applied to ultracold rubidium atoms. The pulses quench the background ground-state molecular population but form bound dimers within the excited state. A pump-probe experiment was designed to chart the excited-state dynamics; however, the oscillations predicted by theoretical calculations were not evident in the molecular signal. The nature of the dynamics is expected to be strongly dependent on the initial state of the atom pairs addressed by the ultrafast pulse: a bound molecular population provides an additional candidate to free atoms. A spectroscopic measurement characterizes these bound molecules and identifies their formation mechanism. A subsequent experiment provides evidence that the predominant contributor to the pump-probe signal is the unbound initial population. The consequences with regard to both the observation of excited-state dynamics and the subsequent application of a dump pulse are discussed.

Jan 1, 20101 citation

Formation of cold molecules by shaping with light the short-range interaction between cold atoms: photoassociation with strong laser pulses

Mihaela Vatasescu

This paper investigates the formation of cold molecules in the photoassociation of two cold atoms by a strong laser pulse applied at short interatomic distances, which lead to molecular dynamics taking place in the light-induced (adiabatic) potentials. A two-electronic-state model in the caesium dimer is used to analyse the effects of this strong coupling regime and to show specific results: (i) acceleration of the ground-state population to the inner zone due to a non-impulsive regime of coupling at short and intermediate interatomic distances, (ii) formation of cold molecules in strongly bound levels of the ground state, where the population at the end of the pulse is much bigger than the population photoassociated in bound levels of the excited state, and (iii) the final momentum distribution of the ground-state wavepacket keeping the signatures of the maxima in the initial wavefunction continuum. It is shown that the topology of the light-induced potentials plays an important role in dynamics.This paper investigates the formation of cold molecules in the photoassociation of two cold atoms by a strong laser pulse applied at short interatomic distances, which lead to molecular dynamics taking place in the light-induced (adiabatic) potentials. A two-electronic-state model in the caesium dimer is used to analyse the effects of this strong coupling regime and to show specific results: (i) acceleration of the ground-state population to the inner zone due to a non-impulsive regime of coupling at short and intermediate interatomic distances, (ii) formation of cold molecules in strongly bound levels of the ground state, where the population at the end of the pulse is much bigger than the population photoassociated in bound levels of the excited state, and (iii) the final momentum distribution of the ground-state wavepacket keeping the signatures of the maxima in the initial wavefunction continuum. It is shown that the topology of the light-induced potentials plays an important role in dynamics.

Journal of Physics B Atomic Molecular and Optical PhysicsJul 22, 200911 citations

Cold molecules formation by shaping with light the short-range interaction between cold atoms: photoassociation with strong laser pulses

Mihaela Vatasescu

The paper investigates cold molecules formation in the photoassociation of two cold atoms by a strong laser pulse applied at short interatomic distances, which lead to a molecular dynamics taking place in the light-induced (adiabatic) potentials. A two electronic states model in the cesium dimer is used to analyse the effects of this strong coupling regime and to show specific results: i) acceleration of the ground state population to the inner zone due to a non-impulsive regime of coupling at short and intermediate interatomic distances; ii) formation of cold molecules in strongly bound levels of the ground state, where the population at the end of the pulse is much bigger than the population photoassociated in bound levels of the excited state; iii) the final momentum distribution of the ground state wavepacket keeping the signatures of the maxima in the initial wavefunction continuum. It is shown that the topology of the light-induced potentials plays an important role in dynamics.The paper investigates cold molecules formation in the photoassociation of two cold atoms by a strong laser pulse applied at short interatomic distances, which lead to a molecular dynamics taking place in the light-induced (adiabatic) potentials. A two electronic states model in the cesium dimer is used to analyse the effects of this strong coupling regime and to show specific results: i) acceleration of the ground state population to the inner zone due to a non-impulsive regime of coupling at short and intermediate interatomic distances; ii) formation of cold molecules in strongly bound levels of the ground state, where the population at the end of the pulse is much bigger than the population photoassociated in bound levels of the excited state; iii) the final momentum distribution of the ground state wavepacket keeping the signatures of the maxima in the initial wavefunction continuum. It is shown that the topology of the light-induced potentials plays an important role in dynamics.

arXiv:0906.1918Jun 10, 20090 citations

We analyze the formation of

{\mathrm{Rb}}_{2}

molecules with short photoassociation pulses applied to a cold

^{85}\mathrm{Rb}

sample. A pump laser pulse couples a continuum level of the ground electronic state

X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}

with bound levels in the

{0}_{u}^{+}(5S+5{P}_{1∕2})

and

{0}_{u}^{+}(5S+5{P}_{3∕2})

5S+5{P}_{1∕2}

asymptote. Weakly bound molecules in the singlet ground or lowest triplet state can be created by a single pulse while the formation of more deeply bound molecules requires a two-color pump-dump scenario. More deeply bound molecules in the singlet ground or lowest triplet state can be produced only if efficient mechanisms for both pump and dump steps exist. While long-range

1∕{R}^{3}

potentials allow for efficient photoassociation, stabilization is facilitated by the resonant spin-orbit coupling of the

{0}_{u}^{+}

states. Molecules in the singlet ground state bound by a few wave numbers can thus be formed. This provides a promising first step toward ground-state molecules which are ultracold in both translational and vibrational degrees of freedom.

{\text{Rb}}_{2}

into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of preassociated molecules.